The anticipated size of the world airliner market over the period 1997-2016, and the resultant requirements for aluminium plate and extrusions to satisfy potential Airbus wing box production is reviewed.

The ‘value’ of technology and the threat posed by polymer composites to the future of aluminium alloys for large transport aircraft wing box structures is discussed and the prospect is raised that there may be limited further development potential for conventional aluminium alloys within the civil transport wing context. This may then force a re-evaluation of the role of aluminium-lithium alloys and other non-conventional metallic materials as alternatives to polymer composites.

Opportunities to maximise the cost-effectiveness of advanced aluminium alloys are discussed and the potential benefits of closer co-operation between the aircraft and aluminium industries highlighted within a joint technical and commercial framework.

The ‘challenge’ to the aluminium industry is described as a continuing requirement to assist the aircraft manufacturer to offer ‘optimum value’ products to the airlines. Otherwise, alternative technologies such as polymer composites will emerge and the pre-eminent position of aluminium in civil transport aircraft will be eroded.

Optical pressure measurement using fluorescent techniques is being widely researched for use in windtunnels. The technique offers global coverage of model surface pressures. A paint, the fluorescence of which is dependent on air pressure, is applied to the surface of a windtunnel model and the pressure distribution is obtained from the intensities measured. There are three principle techniques used to produce the surface pressure distributions: radiometric imaging, lifetime measurement and fluorescent lifetime imaging.

Radiometric imaging produces global images. A constant illumination is used to excite the paint. The fluorescent intensity distribution is dependent on the surface pressure. Error analysis reveals that the technique has the highest precision at low absolute pressures. However, wind-off reference images are required to compensate for illumination and paint non-uniformity. Experimental investigation found that although this is able to compensate for rigid structures, model movement introduces registration and geometric errors. These errors can be corrected by processing at the expense of accuracy.

Lifetime measurement is a technique that uses pulsed illumination. The fluorescent lifetime is dependent on the pressure. A wind-off reference image is not required and error analysis predicts that the technique holds an advantage at high absolute pressures.

Fluorescent lifetime imaging produces global images using a modulated light source to excite the paint. The phase and modulation depth of the fluorescent signal are proportional to the pressure. A wind-off reference image is not required and error analysis predicts that the technique has the same advantages as lifetime imaging. Preliminary results from fluorescent lifetime imaging indicate that this technique can be implemented using robust, solid-state technology.

A method for the solution of the time dependent Euler equations on unstructured grids is presented for unsteady flows about oscillating aerofoils. The flow solver involves a finite volume spatial discretisation and a Runge-Kutta time-stepping scheme. A dynamic mesh algorithm is used for problems where the aerofoil moves and/or deforms. Steady and unsteady results are obtained for single and multi-element aerofoils.

This paper describes a facility for the acquisition of simultaneous high quality particle image velocimetry (PIV) and unsteady surface pressures with high spatial and temporal resolution. The facility, developed through a long-standing collaboration between the Department of Aerospace Engineering at Glasgow University and the Fluid Loading and Instrumentation Centre at Heriot-Watt University, is currently being used in collaborative projects and has the potential to provide a level of detail previously unattainable for CFD validation.

Results from both measurement techniques will be presented to demonstrate the range and potential of the two systems. In addition, the value of combining the two techniques will be demonstrated by results from a blade-vortex interaction experiment in which both methods were applied. Finally, future applications of the combined system will be discussed.

A high order boundary element formulation is presented and applied to the solution of potential, incompressible flows around non-lifting and lifting configurations. The high order numerical algorithm is based on a bicubic interpolation of both geometry and quantities over each element of discretisation of the boundary. Numerical validation of the formulation is performed by studying the aerodynamic solution around fuselages and wings, and making comparisons with existing numerical results.

Flowfield measurements of the blade tip vortices from a rotating helicopter rotor model were performed by three component laser-Doppler velocimetry (3D-LDV) and conventional (two component) particle image velocimetry (PIV). In general, the results are in good correspondence, but also illustrate the different properties of both techniques: LDV offers the capability of three-component measurements, whereas PIV captures the unsteadyness of the flowfield.